The present invention relates to a locking assembly for a typical refuse container which has a receptacle for receiving refuse and a hinged lid that covers the receptacle. The locking assembly locks the lid so that it cannot be manually opened by an unauthorized user, but can be opened automatically by a refuse collection truck when the container is being emptied.
A continuing problem for users of refuse containers is the unauthorized use of their container. The cost of a container is directly related to the number of times the container has to be dumped. Thus, if others are using the container they fill it more quickly and increase the cost of the container.
In order to keep others from using the container, various methods have been employed to lock the container. One method is to wrap chains around the container and lock the chains. With this method, the only way to open the lid is to have a key to unlock the lock and remove the chains. This technique is cumbersome for the user and is bad for the refuse collector. The collector must have a key and when it is time to dump the container, he must get out of his truck and unlock the lock. With several users employing this method the collection truck operator has to keep a collection of keys properly organized and leave the truck numerous times during a route. This dramatically slows the collection process.
U.S. Pat. No. 4,155,584 issued to Pracchia on May 22, 1979, is one attempt to overcome the above problems and still provide a lock for a storage container that does not require the operator of a collection truck to leave the vehicle when the container is to be dumped. Pracchia incorporates a security locking mechanism located completely within the container which is actuated only when the container is turned over.
In one embodiment of Pracchia, a weight is mounted to pivot by gravity through a circular path when the unit is tilted. A hammer carried by the weight strikes an anvil on a crank arm which operates through a toggle connecting link to pivot a locking lever. A detent on the locking lever is moved out of engagement with a perimeter frame which is pivotally mounted on the open end of the container. A closure lid which is independently locked to the frame swings open with the frame for discharging the contents.
In another embodiment a weight is moved by gravity through an arc to strike and pivot a detent arm which normally retains a larger second weight. The second weight then moves by gravity along a linear path towards the end of a tube where it strikes and pivots a locking lever. The lever then moves a detent out of engagement with a perimeter frame which it then is free to swing open with the closure lid for dumping the contents.
A disadvantage of Pracchia is the cost of such a unit. Because of the complicated linkage mechanism employed, it appears to be an expensive refuse collection unit. Additionally, the various moving components would need to be maintained, particularly because the mechanism is operated by gravity which requires the components to move freely. Regular maintenance would have to be performed in order to ensure proper operation. Still further, the unit would not function well with a unit having a plastic lid as is typical of modern receptacles. Pracchia discloses a slot 60 formed in the outer margin of the lid which closes about a staple 62 mounted above the outer angle of the frame so that a padlock can be mounted through the staple for independently locking the lid of the frame. With a plastic lid, an unauthorized user could easily force the lid past the staple and the lock to use the container.
U.S. Pat. No. 4,182,530 issued to Hodge on Jan. 8, 1980 discloses a further attempt at providing a lock for a storage container which does not require the operator of a collection truck to unlock the container when the container is dumped. Hodge discloses a commercial trash bin which has lids provided with a special latch that is disabled to permit dumping through gravity action when the trash bin is lifted, inverted and dumped. In one embodiment the mechanism employs a heavy spring which is compressed by the weight of the trash bin, and in another embodiment a gravity operated latch releasing mechanism is employed. In each, to open the trash bin while it is in the upright orientation, a key-operated release, either in the form of a padlock or a built-in lock mechanism, is used.
One disadvantage of Hodge is that the locking assembly must be made of heavy gauge steel because it supports the weight of the container when the container is being dumped. As illustrated, the latch mechanism pivots on a lateral pivot rod. When the trash container is being dumped, the weight of the container rests upon plate 34 of the latch mechanism with the latch mechanism pivoting about the single lateral pivot rod. If the container is misaligned at all during the dumping process, tremendous stress could be exerted on the pivot rod and unless heavy gauge material is used, it could damage if not destroy the rod and the locking mechanism. Further, the pivot rod would have to be maintained regularly in order to ensure that it works properly. If the rod were to stick due to a build-up of corrosion, the forces would be transmitted again to the pivot rod and again possibly damage or even destroy the locking mechanism. Another disadvantage of Hodge is that the arrangement allows a pry bar to be used to open the container. The upper portion of the locking mechanism is very close to the front face of the container allowing a pry bar to be inserted to pry open the lock assembly to open the lid.